Cellular phones or smart phones, which are equipped with a camera module for fulfilling a function of taking a picture of an object and storing the still image or moving image based on the picture, are continually being developed. A camera module may generally include an image sensor module and a voice coil motor (VCM) for controlling the distance between a lens and the image sensor module.
Information technology products, such as cellular phones, smart phones, tablet PCs, notebook computers and the like, are provided therein with an ultracompact camera module. A voice coil motor may perform auto-focusing for controlling the distance between an image sensor and a lens so as to adjust the focal length of the lens.
A camera module may finely shake due to trembling of user's hand while a picture of an object is being taken. In this regard, in order to correct the distortion of images or moving images caused by the trembling of a user's hand, voice coil motors incorporating optical image stabilizers (OIS) are being developed.
In auto-focusing performed in a lens moving apparatus, a moving position of a bobbin in a first direction is controlled by detecting displacement of the bobbin in the first direction, which is the optical direction.
When an additional position detecting sensor is used in order to detect displacement of a bobbin in the first direction, there is a need to provide an additional PCB to mount the mounting of the position detecting sensor and to provide a structure for securing the PCB to a housing and a bobbin. Consequently, the cost of manufacturing the lens moving apparatus is increased due to the complicated structure, and the space required to install the additional component makes it difficult to realize a lens having large diameter.
In addition, since the additional position detecting sensor exhibits an extremely restricted linear range in its output due to the positional relationship between the position detecting sensor and a magnet, there is a necessity for improvement.